1. Field of the Invention
The present invention is directed to an orientation assistance device for use during image-intensified fluoroscopic examinations of internal structures and operations thereon. The invention is particularly useful in assisting medical personnel by eliminating disorientation during various medical procedures, accelerating the operation and thereby reducing the radiation exposure time.
2. Description of the Prior Art
One of the most routine x-ray examination procedures is fluoroscopy. The primary functions of the fluoroscope is to provide a visualization of the positioning of internal structures and motion of internal fluids, providing diagnostic information to the operator. Fluoroscopy is commonly used in engineering and related sciences, such as metallurgy, to examine structures, including searching for stress, wear, or flaws in various structures and components. Fluoroscopy is also used extensively in the medical field, supplying continuous information to physicians during medical procedures. It is similarly used in veterinary medicine.
Conventional fluoroscopy generates continuous images of internal structures on a fluoroscopic screen during a prolonged energization of the x-ray tube. With the recent introduction of new technological advances, including the application of computer technology to fluoroscopy and radiography, conventional fluoroscopy is quickly being replaced by image-intensified fluoroscopy. Image-intensified fluoroscopy uses a television monitor to display the image, yielding brighter fluoroscopic images than had previous conventional screens. The image-intensified fluoroscopic equipment is often referred to as a "C-arm," as the radiation source, the image-intensifying receiver and the apparatus connecting them is generally in the shape of a "C."
There are two ways of controlling the position of the C-arm during a fluoroscopic procedure; manually and by remote control. Most often, a technician controls the positioning of the C-arm with a remote control panel, centering the apparatus on the internal structure a physician will be operating upon. During medical procedures, a physician can make manual adjustments to the fluoroscope, such as targeting a new portion of a patient's body, changing the C-arm's tilt, and rotating the receiver tube. During medical procedures requiring sterile conditions, the remote control is used for making adjustments as the C-arm is enclosed in plastic. Generally, a technician operates the controls from an adjoining room as it becomes more awkward for the physician to move the plastic enshrouded device.
During medical procedures, the prolonged period of exposure to radiation necessary in fluoroscopic procedures, both to a patient and to medical personnel, has prompted research into methods of reducing the exposure time. Initially it was hoped that the use of image-intensified fluoroscopy, utilizing a television monitor to increase the brightness and resolution of the viewed image, would permit a tenfold reduction in the x-ray tube current, and thereby reduce the extent of exposure to the patient during a fluoroscopic procedure. However, the actual reduction has been far smaller. As a consequence, there has been no significant reduction in the patient's exposure to radiation, still considerably higher than from radiographic examinations.
The image produced on the monitor during a fluoroscopic examination provides no reference points to assist a doctor or technician in determining the orientation of the patient's internal structure. This forces either technicians or physicians to place something, either a radiopaque object or, often, their own hand, directly into the radiation field to help determine the true orientation of the observed body part. During complicated surgery, this can often be a very distracting and time consuming process for the surgeon. The lack of reference also hinders the technician in centering the fluoroscope over the injured area, slowing patient preparation and prolonging the radiation exposure to both the patient and staff members.
Alternative methods of reducing radiation exposure during fluoroscopy are being sought continually. During a medical fluoroscopic examination, the time spent by the technician generally falls in three areas: positioning the equipment and subject for proper irradiation, basically centering the apparatus on the desired area; examining the generated image for diagnostic purposes; and following the progress made by the physician as he operates on the patient, assisting the physician as necessary during the medical procedure. By minimizing the time expended in these three areas, exposure time is reduced for both the patient and technician.
U.S. Pat. No. 4,750,487, issued Jun. 14, 1988, to Zanetti, provides an apparatus used with fluoroscopy in guiding a needle to a target object within a body. U.S. Pat. No. 4,722,336, issued Feb. 2, 1988, to Kim et al., provides an apparatus used in conjunction with a fluoroscope to determining the precise three dimensional coordinates of an internal target, particularly in needle and drill placement for precise medical or surgical procedures, such as chemical injection, biopsy or orthopaedic procedures involving the bone, and a guide for positioning the penetrating instrument. Both of these inventions are useful in reducing exposure time, but only within the third stage of fluoroscopic use, during the medical procedure itself.
It is therefore the primary object of the invention to provide an orientation system which is easily employed by a fluoroscope operator during a fluoroscopic examination.
It is also an object of the present invention to provide a simple device that will allow radiologists or x-ray technicians to properly position a patient for examination during any medical fluoroscopic procedure.
A further object of the invention is to reduce the radiation exposure time to patients and medical staff during medical fluoroscopic procedures.
Another object of the present invention is to provide a device that will aid radiologists in orienting on the internal structure of a patient during fluoroscopic examinations without interfering or hindering the operation of the fluoroscope.
Yet another object of the present invention is to provide a device that can easily be secured to existing fluoroscopes without interfering in their normal operation.
It is a still further object of the present invention to provide an inexpensive device which is easily handled during use with an image-intensifying fluoroscope.
These and other objects of the present invention and the various features and details thereof are hereinafter set forth in the following detailed description of the invention.